... ghrelin requires the attachment of a fatty acid for it to become active. In mammals, ghrelin is encoded by a single gene in the ... Interpretive Summary: Ghrelin is a peptide hormone that plays important roles in stimulating food intake and the release of ... Ghrelin is unique in several ways. It is the only known hormone produced by the gastrointestinal tissue that stimulates food ... The actions of ghrelin and obestatin are mediated by specific receptors present in the cell membranes of tissues that respond ...